Automatic tuning mechanism



Aug. 6,

lNvENToR W/LL/ NOA CK ATTORNEY Patented Aug. 6, 1940 UNITED STATESPATENT OFFICE AUTOMATIC TUNING MECHANISM tion of Germany ApplicationJanuary 23, 1940, Serial No. 315,161 In Germany October 26, 1938 Claims.

Mechanism adapted to tune radio apparatus is known in the art in whichthe station names on the scale member are arranged, for instance,alphabetically rather than in the order of their wave-lengths in orderto facilitate the finding of a desired station. In one arrangement ofthis nature a stop pin serving for the setting is shifted along a slotposteriorly of which is journaled a shaft connected with the rotarycondenser, me- Hl tallic disks being seated upon the said shaft whichare provided with cooperating stops or detents. When the stop pin hasbeen shifted as far as the desired station name, a separate knob servesto turn the rotary condenser until l5 it strikes.

The disadvantage of this known arrangement resides in diflicultmanipulation and operation seeing that two setting means must be used;furthermore, in the fact that a distinct stop disk 20 isrequired foreach station to which the apparatus is to be tuned.

f The present invention creates a simpler solution to the problem toprovide an alphabetic scale in that the moving indicator member of thestation scale is in coupling relation and connection with two contactdisks mounted upon a shaft, one of the said contact disks carrying a rowor bank of contacts of which each one corresponds to the station to betuned to in the sequence and order of the station names on the scale,while the other contact disk has as many contacts in the sequence anddisposition of the corresponding position of the tuning means, such asthe rotary condenser of the receiver. Each contact mounted on one diskin this scheme is conductively united with the corresponding contact(that is, the contact coordinated to the same sending station) of therespective other disk. Two contact brushes, one of which cooperates withthe first contact n disk and is stationary while the other onecooperates with the second contact disk though being connected with thetuning means, are cut in a circuit which arrests a motor setting thetuning means as a'conducting connection is es- 1 tablished between thetwo brushes by way of the contact disks.

Moreover, the scale bearing the station names in alphabetical order ismovable and so designed that essentially only the name of the stationjust no tuned in will be visible behind a window formed in the wall ofthe box or panel. The scale more particularly is borne by a band or tapeconnected with the tuning means so that, even if the scale window isvery reduced in size, the name of the 5 station tuned in will be easilylegible even at a (Cl. Z50-4.0)

greater distance. Scales of this kind have been known in the prior art,fundamentally speaking. But in the customary arrangement of the stationnames in the order of their frequencies, the Search for the sendingstation using a scale of 5 this sort was very difficult and tedious sothat it was recognized that an additional more easily readable scale wasdesirable.

An exemplified embodiment of the invention is shown schematically in thedrawing. The knob D, which slightly projects laterally of the casing orcabinet (not shown) of a receiver and which is to serve for tuning, isseated upon a shaft A1 which supports two disks S1 and S2 made ofinsulation material. In the neighborhood of the periphery, that is, aportion thereof comprising 180 degrees, there are disposed the contactsK1 and K2 which may be in the form of rivets and which extend betweenthe opposite faces of the respective disks. The number of such contactrivets to be mounted upon each disk isgoverned by the number of stationsto be tuned. While the contact rivets are arranged at equal distancesupon the disk S1, they are spaced on disk S2 in accordance with thepositions of the rotary condenser C serving for the tuning when adjustedto the Various stations. The contact rivets K1 are engaged by astationary wiper brush K'i, and the contact rivets K2 are engaged by acontact brush K2 attached by means of an arm or 30 lever A to the shaftof the rotary condenser A2. The shaft A1 drives by way of the dials S1and S2 a web or endless band B stretched out between two journaledrollers W1 and W2 on which the station naines (represented by theletters A, B, C.- to S) are arranged in alphabetical order. Of thesenames only a small part, that is, a part comprising one or a few stationnames is visible posteriorly of a window X shown dotted, fitted in thewall or panel of the receiver (not shown).

Ii' a certain station name appears behind the window after adjustment ofthe rotary knob D, then brush K1 will engage a very definite contactrivet K1 corresponding to the desired station, let us say K. To the samestation corresponds a definite rotary or angular position of the shaftA2 of the rotary condenser in which the brush Kz comes to be placed alsoopposite a very definite contact rivet K on the disk S2. The contactrivets K1 and K2 coordinated to the same 50 sending station, which, ofcourse, are staggered in respect to each other at will so as to suit thedeviation between the alphabetical order and the wavelength sequence,are each united with each other by a lead of which only a few, LL, LHand Lo,

are represented in the drawing. In other words, each conductor or leadconnects corresponding contacts on the disks S1 and S2. For example, theconductor Lu connects the contact O in disk S1 with contact O on diskS2, etc.

Now, arrangements are so made that after setting to a certain station bythe agency of the knob D, the tuning means shaft A2 must trail until thebrush Kz cornes to be positioned opposite the coordinated contact rivetK2, in other words, until conducting connection has been establishedbetween the brushes K1 and K'2 by way of the particular pair of contactsK1, K2.

v corresponding to the desired station and the junction wire, say, LH.This is accomplished by conductively connecting the two brushes by wayof a slide ring K3, a brush contact Ka, a relay L and a source ofpotential supply-Q. When energized the said relay L opens a normallyclosed contact T and thereby interrupts the circuit of a motor M, theshaft of which is connected through the intermediary of the frictionwheels S3 and S4 or other suitable gearing with the shaft A2. In seriesrelation to the switch T and the source of voltagesupply Q' for themotor is a change-over or reversing switch U which is shifted by meansofstops (not shown) on the rotary condenser so that by switching thepotential from a clockwise winding to a winding causative ofcounter-clockwise rotation, or vice versa, the reversal of rotation ofthe setting means is insured.

Hence, the operation of the arrangement as hereinbefore described is asfollows: When ytuning in on a certain station by the aid of the rotaryknob D the circuit which includes the relay winding L is first broken.The motor M is excited as the contact T is automatically closed, and itthus will turn the rotary condenser of the receiver until the desiredposition has been attained. When this happens, the brush K2 engages thecontact rivet K2 corresponding to the desired station and as aconsequence closes, by

` way of a definite lead or conductor, such as Lo,

y The contact rivets may be iitted with soldering i a second motor isprovided therefor.

tags or lugs in order to facilitate the work of establishing theconnections LA-to Ls. In orderV to make it easier to establish theswitch connections it is advisable to apply legends to the contactrivets on the disks with the corresponding call letters or wavelengths.

The Contact rivets could also be spaced around the entire circumferenceof the disks if the arm A is not fitted directly on the rotary condensershaft m, but rather on a shaft connected'therewith vthrough atransmission gear whereby the range of rotation is enlarged to 360degrees. The disks, if desired, could be replaced by drums' orequivalent means.

Also the knob D is preferably not tted directly on the shaft A1, but isconnected therewith through reduction gearing in the usual way. Thedrive of the shaft A1 could also be by motor if A switch mounted on theoutside of the receiver apparatus serves to switch it in and reverse itsrotation.

The potentials for energization of the relay L and of the motor M arepreferably tapped from the power unit of the receiver so that nocurrentwill flow when the set is switched off.

v'The band B bearing the station names is suitably translucent, and thesame is illuminated from the rear in the window behind which it becomesvisible. The station names are arranged in large easily legiblelettering upon the band, the names being alphabetical and equi-spaced.Of course, in exceptional cases the alphabetical order may be departedfrom. For instance, for reception of localstations it may be expedientto provide distinct spaces placed at the beginning of band B. Moreover,the band or ribbon could also be replaced by a disk or a drum. The useof a band, however, makes for particularly good utilization of space.Inasmuch as the conventional full-view scale may be dispensed with it ispossible to design the whole front panel of the apparatus to act as abale for the loudspeaker.

What is claimed is:

1. Automatic tuning mechanism for a radio receiver provided withvariable tuning means, comprising a motor for 'driving said tuningmeans, a pair of adjustable disks, each having a similar series ofcontacts, there being one contact in each series assigned to apredetermined station to be tuned in, a xed contact brush cooperatingwith the contacts of one of the disks, a second contact brush adapted tobe rotated in unison with the tuning means and cooperating with thecontacts on the second disk, a conductor joining each pair of relatedcontacts, one on each disk, a circuit including the contact brushes, anyone of the conductors with their terminating contacts and a relay, saidrelay adapted when said circuit is completed to break the motor circuit,thereby arresting the tuning means at the position of adjustment forreceiving the p-redetermined desired station.

2. Automatic tuning mechanism as dened in claim l wherein the contactson the disk with which the ixed contact brush cooperates are arranged ina predetermined order, and the contacts on the second disk are arrangedaccording towavelength, each bearing a denite relation to an adjustedposition of the tuning means for tuning in the predeterminedY .stationto which the lcontact is assigned'.

3.` Automatic tuning mechanism for a radio receiver provided withvariable tuning means, comprising a motor for driving said tuning means,a pair of disks simultaneously` adjustable step by step, each having anequal number of contacts, there being one contact'on each disk assignedto a predetermined station to 'be tuned in, a iiXed contact brushcooperating with the contactsl of one of the disks, 'a secondcontactbrush adapted to be'rotated in unison with the tuning means andcooperating with the contacts on the vsecond disk, 'a conductor joiningeach pair of contacts, one on each disk, which are assigned to apredetermined station, a circuit including the contact brushes, any oneof the conductors depending upon the adjustment of the disks, thecontacts associated with said conducto-r and a relay, said relay adaptedwhen said circuit is completed to break the motor circuit, therebyarresting the tuning means at the position of adjustment for receivingthe predetermined desired station.

4. Automatic tuning-mechanism'for'a radio receiver provided withvariable tuning means, comprising a motor for driving said tuning means,a pair of manually adjustable disks, an indicator scale actuated by saiddisks and having the station designations appearing thereon in apredetermined sequence, each disk having a plurality of contacts equalin number to the predetermined stations desired to be automaticallytuned in, one of said disks having its contacts arranged in the samesequence as the stations on the indicator scale, a Xed contact brushcooperating with said last mentioned disk, the second disk having itscontacts arranged according to Wavelength, a second contact brushmovable in unison with the tuning means and cooperating with thecontacts on the second disk, a conductor joining each pair of contactsone on each disk, which are assigned to a predetermined station, acircuit including the contact brushes, any one of the conductorsdepending upon the adjustment of the disks, the contacts associated Withsaid conductor and a relay, said relay adapted when said circuit iscompleted to break the motor circuit, thereby arresting the tuning meansat the position of adjustment for receiving the predetermined desiredstation. Y

5. Automatic tuning mechanism for a radio receiver provided withvariable tuning means, comprising a motor for driving said tuning means,a pair of disks mounted on a common shaft, an indicator scale adapted tobe moved in unison with Said disks and having the station designationsappearing thereon in alphabetical sequence, means for adjusting thedisks and scale step by step to one of a predetermined number ofstations, each disk having a series oi contacts arranged adjacent itsperiphery, the number of such contacts on each disk being equal to thenumber of stations desired to be automatically tuned in, one of saiddisks having its contacts arranged in the same sequence as the stationson the indicator scale, a xcd Contact brush cou operating With said lastmentioned disk, the second disk having its contacts arranged accordingto Wavelength, a second contact brush movable in unison With the tuningmeans and angularly adjustable to contact the contacts on the seconddisk, a conductor joining a corresponding pair of contacts, one on eachdisk, which are assigned to a predetermined station, a circuit includingthe contact brushes, any one of the conductors depending upon theadjustment oi` the disks and indicator scale, the contacts associatedWith said conductor and a relay, said relay adapted When said circuit iscompleted to break the motor circuit, thereby arresting the tuning meansat the position of adjustment for receiving the desired station.

WILLI NOACK.

